Means for applying a trimming condenser to a main condenser



March 20, 1934. E. D. KOEPPING 1,951,661

MEANS FOR APPLYING A TRIMMING QONDENSER TO A MAIN CONDENSER Filed July 19, 1930 2 Sheets-Sheet 1 gwueutoz EM/L D. KOE'PP/NG March 20, 1934. D KOEPPlNG 1,951,661

' MEANS FOR APPLYING ATRIMMING CONDENSER TO A MAIN CONDENSER Filed July 19,, 1930- 2 Sheets-Sheet 2 wuawboz Emil D. kbeppz'ny Patented Mar. 20, 1934 UNITED STATES PATENT OFFICE Emil D. Koepping, Haddon Heights, N. 3., as-

signor to Radio Condenser Company Camden,

Application July 19, 1930, Serial No. 469,033

9 Claims.

This invention relates to improvements in the construction of electrical condensers such as are commonly used in radio receiving sets.

The specifications for condensers by different radio receiving set manufacturers vary in many details. Some specify that the unit condensers be equipped with compensating plates whereby the capacity curve of each condenser unit comprising a gang can be varied to suit the circuit 10 conditions of the set; other specifications call for small trimming condensers by which the initial minimum capacity of each condenser can be adjusted; and still other specifications call for both of these features, as well as others which need not be mentioned.

The condenser manufacturer therefore must be in position to furnish condensers that will meet all these requirements, and my present invention is directed to means by which a trimming condenser may be quickly attached or detached from the condenser unit.

It frequently happens that the condenser manufacturer may have a quantity of condensers in stock make up with the compensating plates,

but without any trimming condensers. Since the main condensers have already been made and calibrated, to apply the trimming condenser as it has been applied in the past, would throw out the calibration of the main condensers and this work would have to be done all over again.

It is therefore an object of my invention to provide means for attaching the trimming con-.

denser which will not disturb the normal calibration-curve of the main condenser, so that the standard production of condensers with or without compensating plates may be carried through the. factory and the condensers tested and calibrated ready for shipment. Then on receipt of an order in which the customer desires trimming condensers, and there are none in stock, the stock condensers with or without compensating means may be quickly converted by the addition of the trimming condenser, without disturbing the previous calibrated setting of the main condenser.

' In order to illustrate my invention, I have shown the same in connection with a single unit as well as in a four-gang condenser, but it is to be understood that the invention can be applied 59 to any number of units comprising a gang condenser such as are now usually used in radio re ceiving sets with single dial controls.

In the drawings: 7 Figure 1 illustrates a side elevation of a sin- 'gle unit condenser with the rotor slightly out of position of maximum capacity, and without any trimming condenser.

Figure 2 is a view similar to Figure 1, some oi. the parts being omitted, but showing the trimming condenser in position. 60

Figures 3 is a section on the line 3-3 of Figure 2.

- Figure 4 is a view of a modified construction of insulator carrying the stator and trimmer condenser.

Figure 5 is a modified form of trimmer condenser plate.

Figure 6 is a side view of Figure 5.

Figure 7 is a side elevation of a four-gang condenser showing the rotors in the position of Figure 1, and also showing the forms of trimmer plates of Figures 2 and 5.

In the drawings, 1 is a frame having end support plates 2 and 3 carrying. a shaft 4 supported by anti-friction bearing members carried in 76 the races 5 and 6. On the shaft 4, is mounted a sleeve 7, or in case of a gang condenser, a plurality of sleeves 7, each carrying a plurality of rotor plates 8, the ends of which are fastened together by a tie bar 9. In the form shown, each rotor is 80 provided with capacity compensating plates 10 positioned on each side of the rotor.

A quick detachable rotor brake and contact wiper 11 applies a certain amount of friction directly to the end or ends of the sleeve or sleeves 7 to hold the rotor in any position to which it may be turned by the shaft 4. The device 11 also serves to secure a good electrical connection with the rotor or rotors, when the condenser is used in gangs. As shown in Figure 7, each unit of the gang is separated by a shield and brace plate 39 and the members 11 are mounted thereon, as well as on the end plates 2- and 3. This improvement is the subject of another application and will not be further described herein.

The opposite sides of the frame 1 are provided with openings 12, and to that part of the frame 1 forming the lower part of each of the openings 12, there is attached an insulator 13. In the form shown, each of the insulators 13 is fastened to the frame 1 by rivets 14 which preferably fit snugly in holes 38. To the other end of each of the insulators 13, are attached, by means of two screws 16 and 17 passing through good clearance holes 35, tie-bars 15 carrying stator plates 18. Instead of the-screws l6 and l'l-being threaded into the tie bars 15, they are threaded into a clamping bar 19, all as set forth and claimed in application S. N. 465,287, filed by Stanley 8. Cramer on July 2, 1930. a

' 22 comprising one element In addition to the holes provided for the two rivets 14 and the screws 16 and 1'7, each of the insulators 13, as shown in Figure 1, is provided with holes 20 preferably positioned centrally on the insulator 13. The lower of the two holes 20, as shown, may be used for another rivet 14 if desired, while the upper of the two holes 20 is used to receive a screw 21 for attaching a plate of the trimming. condenser. Each of the insulators 13 is also provided with openings 23 arranged on opposite sides of the upper hole 20.. As shown in Figure 1, the

openings 23 are rectangular in shape and are adapted to receive projections. or clips 24, (see Fig. 2) which are bent inwardly from opposite sides of the trimmer plate 22. The trimmer plate 22 is thus seated on the insulator 13 and is bent outwardly and upwardly so as to extend over that portion of the framework of the condenser above the opening 12. At the same time, the metal is bowed at 31 on opposite sides of the small orifice 32, whereby the trimmer plate will always put a tension on the insulator 28 and screw 25, preventing the latter from accidentally changing its position and also automatically following the adjustments of the screw 25 which passes through an opening 26 in the trimmer plate 22 and enters a tapped hole 27 in the frame.

The insulator 28 insulates the screw 25 from the plate 22 and a loosely positionedinsulator 29, preferably'of mica, carried by the screw 25, is positioned between the trimmer plate 22 and the frame 1. Attachment to the trimmer plate is made through the medium of a lug 30 and the eilect of the small capacity of the trimmer plate can be varied by means of the adjusting screw 25, since the screw 21 makes connection with the stator tie bar as already explained.

By providing the insulators 13 with the holes 20 and openings 23, the condenser units may be assembled as shown in Figures 2 and 7, and the main condenser or units adjusted and calibrated and placed in stock. Then, as has already been pointed out, if it is desired to add a trimmer condenser plate 22 either on one or both sides of each condenser unit, this may be quickly done by placing the trimmer plate in the position shown in Figures 2 and 7 and applying the screws 21 and 25 with the insulators 28 and 29.

Heretofore, it has been the practice to carry the trimmer condenser plate by the screws 16 and 17, but after a condenser has once been adjusted and calibrated, subsequent loosening of the screws 16 and 17 to apply a trimmer plate, will immediately throw out the calibration as the stator group of plates are bound to shift when the screws 16 and 17 are loosened. Instead of using the openings 23 and cooperating clips 24 to position the trimmer plate, I may use notches 33 (see Fig. 4) and cooperating projections 37 (Fig. 6) formed in the trimmer plate. As a further alternative construction, holes 34 may be perforated in the insulator 13 and depressions 38 formed in the trimmer plate to fit in the holes 34. Still other positioning means may be utilized.

From what has been said, it will be seen that I have provided a means for applying atrimmer condenser without in any way disturbing or upsetting the work which has already been performed on the main condenser.

Having thus described my invention, what I claim is:

1. In a main condenser having a frame and fixed and movable groups of plates carried by the frame, said fixed group of plates mounting means supported by insulators at-' tached to the frame; means for applying a trimming condenser to the main condenser consisting of, a plate having a hole, an independent attachment screw going through said hole and the insulator into said fixed group mounting means, said plate overlying a part of the frame and having an orifice in this overlying part, an adjusting screw going through said orifice into the frame, and at least one dowel clip for engaging an opening in the insulator.

2. In a main condenser having a frame and. fixed and movable groups of plates carried by the frame, said fixed group of plates having mounting means supported by insulators attached to the frame; means for applying a trimming condenser to the main condenser consisting of, a plate adapted to be mounted on the insulator and overlapping a part of the main condenser frame, said plate mounting comprising an indeendent screw going through the plate and insulator into said fixed group mounting means, and a pair of dowel clips engaging openings in the insulator, and means for adjusting the plate with respect to the frame.

3. In a main condenser having a frame, stator and rotor groups of plates, said stator group of plates being held together by a plurality of means fastened to insulators carried by the frame; means for applying a trimming condenser to the main condenser consisting of a plate having a part to overlap a part of the frame, another part to rest on one of said insulators and having at least one dowel clip, said insulator having an opening for said clip, and a hole to receive an independent mounting screw which goes through the plate and insulator intoone of said stator-holding means, and means for adjusting the plate with respect to the frame.

4. A main condenser having a frame, stator and rotor groups of plates, said stator group of plates being held together by a plurality of means fastened to insulators carried by the frame, at least one of said insulators being provided with a plurality of holes independent of those used for fastening the stator thereto, said independent holes being used for fastening a trimmer condenser plate thereto, said trimmer plate extending over a part of the frame, said frame part being tapped to receive an adjusting screw for adjusting said trimmer plate when the same is used.

5. Quick attachment means for applying a trimming condenser to a main condenser having its stator carried by insulators supported 130 on a frame, comprising holes in at least one of the insulators carrying the stator, independent of the holes used for mounting the stator, a plate adapted to be mounted on the insulator through the medium of said holes and an adjusting screw 135 passing through said plate into the frame but insulated from the plate, and a second insulator carried by said adjusting screw for keeping the plate from contacting with the frame.

6. Quick attachment means for applying a trimming condenser to a main condenser having its stator carried by insulators supported on aframe; comprising a screw hole in at least one of the insulators carrying thestator, independent of the holes used for mounting the 4 stator, a trimmer condenser plate adapted to be mounted on the insulator through the medium of said screw hole, an adjusting screw passing through said plate into the frame but insulated from the plate, a second insulator carried between the plate and frame, and means for keeping the plate from shifting laterally on the insulator.

7. In an electrical condenser having a frame and relatively movable sets of elements carried thereon, one set being supported on at least two insulators carried by the frame, a trimmer condenser plate adapted to be quickly mounted on the insulator by means independent of other mounting devices on the condenser, and means for adjusting the capacity position of said plate with respect to the frame.

8. In an electrical condenser having a frani and relatively movable sets of elements carried thereon, one set being supported on at least two insulators carried by the frame, a trimmer condenser plate adapted to be quickly mounted on the insulator by means independent of other mounting devices on the condenser, means for adjusting the capacity position of said plate with respect to the frame, said trimmer plate having arfold intermediate its length whereby it will respond to the movements of the adjusting means.

9. In a main condenser having a frame, stator and rotor groups of plates,said stator group of plates being held together by a plurality of means fastened to insulators carried by the frame; means for applying a trimming condenser to the main condenser consisting of; a plate having a part to overlap a part of the frame, another part to rest on one of said insulators, said plate having the said two parts offset and some of the material removed adjacent the oflset forming an orifice, and the material on opposite sides of the orifice bowed, whereby the free end of the plate will respond to ,an adjusting means,

means for positively "positioning the plate on the insulator, and means for adjusting the free end of the plate with respect to the frame.

EMIL D. KOEPPING. 

